Permeable friction course (PFC), or new generation open-graded friction course (OGFC) mixtures, are hot mix asphalt (HMA) characterized by high total air voids (AV) content (minimum 18 %) as compared to the most commonly used dense-graded HMA. The high AV content confers to PFC mixtures both high permeability and noise reduction effectiveness. These characteristics and the high values of surface friction exhibited by PFC mixtures, as compared to dense-graded HMA, lead to improvements in safety and the environment, which make PFC one of the safest, cleanest, and quietest alternatives currently available for surface paving. The main objective of this study was improving the current PFC mix design method and construction practices in terms of compaction control. Corresponding results were integrated in an improved mix design method that is based on the guidelines of the current mix design method used by the Texas Department of Transportation. The improved mix design included modified computation of the inputs required to determine mixture density (or corresponding total AV content). These changes led to a proposed modification of the density specification for mix design from 78-82 % to 76-80 %. In addition, the water-accessible AV content was proposed as a surrogate of the total AV content for mix design and evaluation. The improved mix design method also includes verification of drainability, durability, and stone-on-stone contact. Computation of the expected value of permeability (E[k]) and measurement of the water flow value were recommended, respectively, for verification of drainability in the laboratory (using specimens compacted in the Superpave Gyratory Compactor (SGC)) and in the field. The Cantabro loss test conducted in both dry- and wet-conditions was suggested for assessing mixture durability. Improved criteria were proposed for verification of stone-on-stone contact based on the evaluation of the AV content in the coarse aggregate fraction of the mixture. In addition, comparison of the internal structure of field-and laboratory-compacted mixtures supported recommendation of a field-compaction control. Recommendations to reduce the horizontal heterogeneity of AV encountered in PFC specimens included using road cores with a minimum 152.4 mm diameter and coring SGC specimens from 152.4 to 101.6 mm in diameter

O final da vida útil de pavimentos com bases rígidas se caracteriza pelo aparecimento de trincas de blocos e de fadiga. Neste cenário, a reciclagem das camadas de base e revestimento asfáltico, com adição de cimento, surge como técnica importante para reabilitação dessas estruturas. Além de se tratar de uma solução vantajosa do ponto de vista técnico, é competitiva em termos econômicos, além de sustentável. Entretanto, a escassa normatização nacional dificulta sua aplicação, destacando-se a falta de um procedimento de dosagem. Objetivando contribuir para o desenvolvimento de um método de dosagem de camadas recicladas com cimento, desenvolveu-se um programa experimental, contemplando a caracterização mecânica (resistência e rigidez), a variação volumétrica e a erodibilidade de misturas contendo fresado asfáltico, materiais de bases rígidas (brita graduada tratada com cimento e solo-cimento) e cimento Portland. Foram analisados os efeitos da porcentagem de fresado, do teor de cimento e do tempo de cura, compactando-se os corpos de prova na energia Modificada. Com auxílio de um software estatístico, foi elaborado um planejamento experimental para definição das misturas analisadas, contemplando-se diversos níveis para as variáveis independentes (teores de cimento entre 1% e 7%, e porcentagens de fresado variando entre 8% e 92%, aproximadamente). Os tempos de cura considerados foram extrínsecos ao planejamento e variaram de acordo com o ensaio, sendo de 3, 7 e 14 dias para os ensaios de comportamento mecânico e de 7 dias para os demais ensaios. Obtiveram-se modelos com efeitos estatisticamente significativos, com exceção da expansão. Os demais modelos apresentaram coeficientes de determinação de médios a elevados, tendo em vista a heterogeneidade dos materiais estudados, além do tamanho amostral considerável. Foi verificado que todas as variáveis afetam as propriedades analisadas, sendo que o teor de cimento demonstrou maior efeito, sendo que sua adição melhora consideravelmente o comportamento das misturas empregadas, frente à ação do tráfego e da água. Foram alcançados resultados bastante elevados de resistência à compressão simples (1,00 MPa a 6,49 MPa) e resistência à tração na compressão diametral (0,17 MPa a 1,22 MPa); já a rigidez das misturas apresentou uma ampla variação de resultados (484 MPa a 20.031 MPa). Com relação aos materiais de base empregados (brita graduada tratada com cimento e solo-cimento), não se observou uma tendência única; as misturas com solo-cimento apresentaram maior resistência, entretanto, com comportamento ligeiramente inferior quanto à variação volumétrica e à erodibilidade. Na análise da rigidez, os materiais de base mostraram comportamento bastante similar. Para concluir, foi verificado que o procedimento proposto por Fedrigo (2015) também é satisfatório para a dosagem de misturas recicladas constituídas por antigas bases cimentadas e fresado asfáltico, restando ainda quantificar a possível retração por secagem das misturas estudadas. / The end of the useful life of pavements with rigid bases characterizes by the appearance of block and fatigue cracking. The full-depth reclamation with cement (FDR-C) of this layer combined with the asphalt layer seem to be a good choice for the rehabilitation of the pavement structure. Besides being an advantageous solution from a technical point of view, it is competitive in economic terms, besides being sustainable. However, the Brazilian standards are scarce thus limiting its application, highlighting the lack of an appropriated mix design method to this technique. In order to contribute for the development of an FDR-C mix design method, an experimental program was developed aiming to test the mechanical characterization (strength and stiffness), volumetric variation and the erodibility of mixtures made of reclaimed asphalt pavement (RAP), rigid base materials (cement treated crushed stone and soil-cement) and Portland cement. There were analyzed the effects of the RAP percentage, the cement content and the curing time of the specimens. For that, the compaction effort used was the Brazilian Modified one. Through a statistic software, an experimental planning was prepared for mixtures determination, with several levels for the independent variables (cement content between 1% and 7%, and RAP percentage varying by 8% up to 92%, approximately). The curing time analyzed was outward of experimental planning and it varied according to the kind of test. The specimens of mechanical performance were cured for 3, 7 and 14 days, and the other tests were examined at the 7th day of curing time. Models with statically significant effects were obtained, except the swell one. The others had medium and high coefficients of determination, given the heterogeneity of the studied materials, in addition to considerable sample size. It was found that all variables affect the analyzed properties, and the cement content proved to be with the greatest effect among the analyzed factors. Cement addition improves considerably the behavior of the mixtures for the traffic and water actions. Moreover, higher results were achieved for UCS (1.00 MPa up to 6.49 MPa) and ITS (0.17 MPa up to 1.22 MPa) tests. While the mixtures stiffness presented a wide range of results (484 MPa up to 20,031 MPa). Regarding the studied materials, it was observed that they do not have a single trend. The mixtures with soil-cement presented stronger, but with slightly lower behavior for volumetric variation and erodibility. At the stiffness analysis, different materials showed very similar behavior. All in all, it was found that the mix design method proposed by Fedrigo (2015) is also suitable for employment in semi-rigid FDR-C, still remaining to measure the possible drying shrinkage of specimens.

A energia elétrica é, sem dúvida, um recurso indispensável para a sociedade moderna. A mesma revolucionou o modo de vida do ser humano em todos os aspectos e melhorou substancialmente sua qualidade de vida. A distribuição da energia elétrica cabe ao Sistema Elétrico de Potência – SEP, dividido basicamente em três macro setores: geração, transmissão e distribuição. A eletricidade é efetivamente entregue aos consumidores pelo sistema de distribuição, formado principalmente por redes aéreas sustentadas por postes, estes na sua maioria, feitos de concreto armado. Tendo em vista o adequado fornecimento da energia elétrica à sociedade, se faz necessário assegurar as linhas de distribuição de energia, na qual os postes exercem papel fundamental. Entende-se que o aumento da vida útil dos postes de concreto armado pode colaborar para a redução da manutenção da rede de distribuição, reduzindo o investimento em substituições ou reparos em postes por parte das concessionárias Deste modo, esse trabalho propõe a otimização do traço utilizado na produção de postes de concreto armado em uma empresa de artefatos de concreto, visando à vida útil do mesmo. Para tanto foram realizados estudos visando o aprimoramento da composição dos agregados, adição de material pozolânico, adição de fibras e utilização de aditivos superplastificantes. Para análise dos traços em escala real foram moldados 12 postes, tipo duplo T com 9 metros de comprimento, empregando 5 traços com características distintas. Os postes foram avaliados seguindo a metodologia e requisitos da NBR 8451-1 (ABNT, 2011), parâmetros de resistência mecânica do concreto e penetração de íons cloreto ASTM C1202 (2012). Por meio da análise dos resultados, é apresentado o traço indicado para produção de postes de concreto armado, onde foi possível aprimorar o traço atualmente produzido pela empresa, reduzindo o consumo de cimento de 429 kg/m³ para 351 kg/m³ e reduzindo a taxa de penetração de íons cloreto e aumentando a vida útil do poste de concreto armado de 10 para 60 anos. À vista disso, foi possível aumentar a vida útil do elemento, mesmo com a redução do consumo de cimento e o custo para a produção do traço de concreto. / Electricity is undoubtedly an indispensable resource for modern society. The same has revolutionized the way of life of the human being in all aspects and substantially improved their quality of life. The distribution of electricity is up to the Electric Power System - EPS, basically divided into three macro sectors: generation, transmission and distribution. Electricity is actually delivered to consumers by the distribution system, consisting mainly of overhead lines supported by pylons, these mostly made of reinforced concrete. Given the adequate supply of electricity to society, it is necessary to ensure the power distribution lines, in which the poles play a fundamental role. It is understood that increasing the useful life of reinforced concrete poles can contribute to the reduction of maintenance of the distribution network, reducing investment in replacements or repairs on poles by concessionaires. Thus, this paper proposes the optimal trait used in the production of reinforced concrete poles on a firm concrete artifacts, seeking the life of it For both studies were performed in order to improve the composition of households, adding pozzolanic material, adding fiber and use of superplasticizers additives. For analysis of traces in real scale 12 posts, T type double with 9 feet long, employing five traits were shaped with distinct characteristics. The posts were evaluated following the methodology and requirements of NBR 8451-1 (ABNT, 2011), the mechanical response of concrete and chloride ion penetration ASTM C1202 (2012). By analyzing the results, the dash indicated for production of reinforced concrete poles, where it was possible to improve the trace currently produced by the company, reducing the cement content of 429 kg / m³ to 351 kg / m³ and reducing the rate appears penetration of chloride ions and increasing the service life of reinforced concrete post 10 to 60 years. In view of this, it was possible to extend the life of the element, even with the reduction in cement consumption and the cost for the production of concrete mix.

A energia elétrica é, sem dúvida, um recurso indispensável para a sociedade moderna. A mesma revolucionou o modo de vida do ser humano em todos os aspectos e melhorou substancialmente sua qualidade de vida. A distribuição da energia elétrica cabe ao Sistema Elétrico de Potência – SEP, dividido basicamente em três macro setores: geração, transmissão e distribuição. A eletricidade é efetivamente entregue aos consumidores pelo sistema de distribuição, formado principalmente por redes aéreas sustentadas por postes, estes na sua maioria, feitos de concreto armado. Tendo em vista o adequado fornecimento da energia elétrica à sociedade, se faz necessário assegurar as linhas de distribuição de energia, na qual os postes exercem papel fundamental. Entende-se que o aumento da vida útil dos postes de concreto armado pode colaborar para a redução da manutenção da rede de distribuição, reduzindo o investimento em substituições ou reparos em postes por parte das concessionárias Deste modo, esse trabalho propõe a otimização do traço utilizado na produção de postes de concreto armado em uma empresa de artefatos de concreto, visando à vida útil do mesmo. Para tanto foram realizados estudos visando o aprimoramento da composição dos agregados, adição de material pozolânico, adição de fibras e utilização de aditivos superplastificantes. Para análise dos traços em escala real foram moldados 12 postes, tipo duplo T com 9 metros de comprimento, empregando 5 traços com características distintas. Os postes foram avaliados seguindo a metodologia e requisitos da NBR 8451-1 (ABNT, 2011), parâmetros de resistência mecânica do concreto e penetração de íons cloreto ASTM C1202 (2012). Por meio da análise dos resultados, é apresentado o traço indicado para produção de postes de concreto armado, onde foi possível aprimorar o traço atualmente produzido pela empresa, reduzindo o consumo de cimento de 429 kg/m³ para 351 kg/m³ e reduzindo a taxa de penetração de íons cloreto e aumentando a vida útil do poste de concreto armado de 10 para 60 anos. À vista disso, foi possível aumentar a vida útil do elemento, mesmo com a redução do consumo de cimento e o custo para a produção do traço de concreto. / Electricity is undoubtedly an indispensable resource for modern society. The same has revolutionized the way of life of the human being in all aspects and substantially improved their quality of life. The distribution of electricity is up to the Electric Power System - EPS, basically divided into three macro sectors: generation, transmission and distribution. Electricity is actually delivered to consumers by the distribution system, consisting mainly of overhead lines supported by pylons, these mostly made of reinforced concrete. Given the adequate supply of electricity to society, it is necessary to ensure the power distribution lines, in which the poles play a fundamental role. It is understood that increasing the useful life of reinforced concrete poles can contribute to the reduction of maintenance of the distribution network, reducing investment in replacements or repairs on poles by concessionaires. Thus, this paper proposes the optimal trait used in the production of reinforced concrete poles on a firm concrete artifacts, seeking the life of it For both studies were performed in order to improve the composition of households, adding pozzolanic material, adding fiber and use of superplasticizers additives. For analysis of traces in real scale 12 posts, T type double with 9 feet long, employing five traits were shaped with distinct characteristics. The posts were evaluated following the methodology and requirements of NBR 8451-1 (ABNT, 2011), the mechanical response of concrete and chloride ion penetration ASTM C1202 (2012). By analyzing the results, the dash indicated for production of reinforced concrete poles, where it was possible to improve the trace currently produced by the company, reducing the cement content of 429 kg / m³ to 351 kg / m³ and reducing the rate appears penetration of chloride ions and increasing the service life of reinforced concrete post 10 to 60 years. In view of this, it was possible to extend the life of the element, even with the reduction in cement consumption and the cost for the production of concrete mix.

O final da vida útil de pavimentos com bases rígidas se caracteriza pelo aparecimento de trincas de blocos e de fadiga. Neste cenário, a reciclagem das camadas de base e revestimento asfáltico, com adição de cimento, surge como técnica importante para reabilitação dessas estruturas. Além de se tratar de uma solução vantajosa do ponto de vista técnico, é competitiva em termos econômicos, além de sustentável. Entretanto, a escassa normatização nacional dificulta sua aplicação, destacando-se a falta de um procedimento de dosagem. Objetivando contribuir para o desenvolvimento de um método de dosagem de camadas recicladas com cimento, desenvolveu-se um programa experimental, contemplando a caracterização mecânica (resistência e rigidez), a variação volumétrica e a erodibilidade de misturas contendo fresado asfáltico, materiais de bases rígidas (brita graduada tratada com cimento e solo-cimento) e cimento Portland. Foram analisados os efeitos da porcentagem de fresado, do teor de cimento e do tempo de cura, compactando-se os corpos de prova na energia Modificada. Com auxílio de um software estatístico, foi elaborado um planejamento experimental para definição das misturas analisadas, contemplando-se diversos níveis para as variáveis independentes (teores de cimento entre 1% e 7%, e porcentagens de fresado variando entre 8% e 92%, aproximadamente). Os tempos de cura considerados foram extrínsecos ao planejamento e variaram de acordo com o ensaio, sendo de 3, 7 e 14 dias para os ensaios de comportamento mecânico e de 7 dias para os demais ensaios. Obtiveram-se modelos com efeitos estatisticamente significativos, com exceção da expansão. Os demais modelos apresentaram coeficientes de determinação de médios a elevados, tendo em vista a heterogeneidade dos materiais estudados, além do tamanho amostral considerável. Foi verificado que todas as variáveis afetam as propriedades analisadas, sendo que o teor de cimento demonstrou maior efeito, sendo que sua adição melhora consideravelmente o comportamento das misturas empregadas, frente à ação do tráfego e da água. Foram alcançados resultados bastante elevados de resistência à compressão simples (1,00 MPa a 6,49 MPa) e resistência à tração na compressão diametral (0,17 MPa a 1,22 MPa); já a rigidez das misturas apresentou uma ampla variação de resultados (484 MPa a 20.031 MPa). Com relação aos materiais de base empregados (brita graduada tratada com cimento e solo-cimento), não se observou uma tendência única; as misturas com solo-cimento apresentaram maior resistência, entretanto, com comportamento ligeiramente inferior quanto à variação volumétrica e à erodibilidade. Na análise da rigidez, os materiais de base mostraram comportamento bastante similar. Para concluir, foi verificado que o procedimento proposto por Fedrigo (2015) também é satisfatório para a dosagem de misturas recicladas constituídas por antigas bases cimentadas e fresado asfáltico, restando ainda quantificar a possível retração por secagem das misturas estudadas. / The end of the useful life of pavements with rigid bases characterizes by the appearance of block and fatigue cracking. The full-depth reclamation with cement (FDR-C) of this layer combined with the asphalt layer seem to be a good choice for the rehabilitation of the pavement structure. Besides being an advantageous solution from a technical point of view, it is competitive in economic terms, besides being sustainable. However, the Brazilian standards are scarce thus limiting its application, highlighting the lack of an appropriated mix design method to this technique. In order to contribute for the development of an FDR-C mix design method, an experimental program was developed aiming to test the mechanical characterization (strength and stiffness), volumetric variation and the erodibility of mixtures made of reclaimed asphalt pavement (RAP), rigid base materials (cement treated crushed stone and soil-cement) and Portland cement. There were analyzed the effects of the RAP percentage, the cement content and the curing time of the specimens. For that, the compaction effort used was the Brazilian Modified one. Through a statistic software, an experimental planning was prepared for mixtures determination, with several levels for the independent variables (cement content between 1% and 7%, and RAP percentage varying by 8% up to 92%, approximately). The curing time analyzed was outward of experimental planning and it varied according to the kind of test. The specimens of mechanical performance were cured for 3, 7 and 14 days, and the other tests were examined at the 7th day of curing time. Models with statically significant effects were obtained, except the swell one. The others had medium and high coefficients of determination, given the heterogeneity of the studied materials, in addition to considerable sample size. It was found that all variables affect the analyzed properties, and the cement content proved to be with the greatest effect among the analyzed factors. Cement addition improves considerably the behavior of the mixtures for the traffic and water actions. Moreover, higher results were achieved for UCS (1.00 MPa up to 6.49 MPa) and ITS (0.17 MPa up to 1.22 MPa) tests. While the mixtures stiffness presented a wide range of results (484 MPa up to 20,031 MPa). Regarding the studied materials, it was observed that they do not have a single trend. The mixtures with soil-cement presented stronger, but with slightly lower behavior for volumetric variation and erodibility. At the stiffness analysis, different materials showed very similar behavior. All in all, it was found that the mix design method proposed by Fedrigo (2015) is also suitable for employment in semi-rigid FDR-C, still remaining to measure the possible drying shrinkage of specimens.

Concreto projetado é aquele pneumaticamente transportado e projetado a alta velocidade, sobre uma superficie, sendo auto-compactado. Assim, denota-se que suas propriedades são dependentes do processo de projeção utilizado. Desta forma, para se estudar o material, é importante ter-se o conhecimento do seu processo de produção (se por via seca ou úmida, equipamentos e mão-de-obra utilizados, etc.) e das propriedades especificas do concreto projetado (como a reflexão, o desplacamento e a liberação de poeira ou névoa) e as respectivas formas de controle. Foi executado o estudo experimental do concreto projetado via seca, onde foi possivel caracterizar algumas diferenças de comportamento em relação ao concreto convencional. Entre elas está o fato de que a maior compactação e resistência mecânica é obtida com o teor ótimo da mistura e não com a menor relação água/cimento. Constatou-se o fato da projeção do concreto no teto fornecer um material de melhor qualidade que aquele projetado na parede. Finalmente, para a obtenção de um material boa qualidade, é fundamental o controle rigoroso do teor de aditivo acelerador, a utilização de bicos afunilados, pressão de ar comprimido adequada, pré-umidificação com injeção de água sob pressão e seguir as recomendações para o controle da qualidade do processo de projeção como um todo. / Shotcrete is concrete pneumatically conveyed and projected at high speed onto a surface, compacting itself. Thus its properties depend on the shooting process. It is important to know the shooting process (wet ou dry-mix process, equipaments and working crew, etc.), the specific properties of shotcrete (rebound, sloughing and dust generation) and respective mean of controlo An experimental study was made using dry-mix shotcrete, where it was possible to point out some differences of the plain concrete analysis. One of these is the high compaction and stregth achieved with the optimum waterIdry materiaIs ratio and not the minimum water/cement ratio. Shotcrete, gunned in overhead, generates a better material compared to the vertical walls. Finally, to obtain a good quality material, it\'s very important to make a rigorous control of the accelerator admixture contento AIso, it is recommended to use a funnelshaped nozzle, adequate compressed air pressure, hidromix with high water pressure and to follow the recommendations on alI shotcreting process quality control.

The Deep Mixing Method (DMM) is a widely used, in-situ ground improvement technique that modifies and improves the engineering properties of soil by blending the soil with a cementitious binder. Laboratory specimens were prepared to represent soil improved by the wet method of deep mixing, in which the binder is delivered in the form of a cement-water slurry. To study the influence of curing temperature on the strength of the treated soil, specimens were cured in temperature-controlled water baths for the desired curing time. After curing, unconfined compressive strength (UCS) tests were conducted on the specimens. To investigate the optimum mix design for the wet method of deep mixing, UCS tests were performed to measure the strength of cured specimens, and laboratory miniature vane shear tests were conducted on uncured specimens to measure the undrained shear strength (su), which is used to represent the consistency of the mixture right after mixing. The consistency is important for field mixing because a softer mixture is easier to mix thoroughly. Based on the UCS test results, an equation that can provide a good fit to the strength data of the cured binder-treated soil is proposed. When the curing temperature was changed during curing, the UCS of the specimen cured at a low temperature and then cured at a high temperature was greater than the UCS of the specimen cured at a high temperature first. This seems to be due to different effects of elevated curing temperatures at early and late curing times on the cement reaction rates, such that elevating the curing temperature later produces a more constant reaction rate, which contributes to the reaction efficiency. An optimum mix design that minimizes the amount of binder while satisfying both a target strength of the cured mixture and a target consistency of the uncured mixture can be established by using the fitted equations for UCS and su. The amount of binder required for the optimum mix design increases as the plasticity of the base soil increases and the water content of the base soil (wbase soil) decreases. / Master of Science / The Deep Mixing Method (DMM) is a ground improvement technique widely used to improve the strength and stiffness of loose sands, soft clays, and organic soils. The DMM is useful for both inland and coastal construction. There are two types of deep mixing. The dry method of deep mixing involves adding the binder in the form of dry powder, and the wet method of deep mixing involves mixing binder-water slurry with the soil. The strength of the cured mixture is significantly influenced by the amount of added cement and water, the curing time, and the curing temperature. This research evaluates the influence of curing temperature on the strength of cured cement-treated soil mixture. Mixture proportions and curing conditions also influence the consistency of the mixture right after mixing, which is important because it affects the amount of mixing energy necessary to thoroughly mix the binder slurry with the soil. This research developed and evaluated fitting equations that correlate the cured mixture strength and the uncured mixture consistency with mixture proportions and curing conditions. These fitting equations can then be used to select an economical and practical mix design method that minimizes the amount of binder needed to achieve both the desired cured strength and uncured consistency. The amount of binder required for the optimum mix design increases as the plasticity of the base soil increases and the water content of the base soil (wbase soil) decreases.

Abstract : Although concrete is a relatively green material, the astronomical volume of concrete produced worldwide annually places the concrete construction sector among the noticeable contributors to the global warming. The most polluting constituent of concrete is cement due to its production process which releases, on average, 0.83 kg CO[subscript 2] per kg of cement. Self-consolidating concrete (SCC), a type of concrete that can fill in the formwork without external vibration, is a technology that can offer a solution to the sustainability issues of concrete industry. However, all of the workability requirements of SCC originate from a higher powder content (compared to conventional concrete) which can increase both the cost of construction and the environmental impact of SCC for some applications. Ecological SCC, Eco-SCC, is a recent development combing the advantages of SCC and a significantly lower powder content. The maximum powder content of this concrete, intended for building and commercial construction, is limited to 315 kg/m[superscript 3]. Nevertheless, designing Eco-SCC can be challenging since a delicate balance between different ingredients of this concrete is required to secure a satisfactory mixture. In this Ph.D. program, the principal objective is to develop a systematic design method to produce Eco-SCC. Since the particle lattice effect (PLE) is a key parameter to design stable Eco-SCC mixtures and is not well understood, in the first phase of this research, this phenomenon is studied. The focus in this phase is on the effect of particle-size distribution (PSD) on the PLE and stability of model mixtures as well as SCC. In the second phase, the design protocol is developed, and the properties of obtained Eco-SCC mixtures in both fresh and hardened states are evaluated. Since the assessment of robustness is crucial for successful production of concrete on large-scale, in the final phase of this work, the robustness of one the best-performing mixtures of Phase II is examined. It was found that increasing the volume fraction of a stable size-class results in an increase in the stability of that class, which in turn contributes to a higher PLE of the granular skeleton and better stability of the system. It was shown that a continuous PSD in which the volume fraction of each size class is larger than the consecutive coarser class can increase the PLE. Using such PSD was shown to allow for a substantial increase in the fluidity of SCC mixture without compromising the segregation resistance. An index to predict the segregation potential of a suspension of particles in a yield stress fluid was proposed. In the second phase of the dissertation, a five-step design method for Eco-SCC was established. The design protocol started with the determination of powder and water contents followed by the optimization of sand and coarse aggregate volume fractions according to an ideal PSD model (Funk and Dinger). The powder composition was optimized in the third step to minimize the water demand while securing adequate performance in the hardened state. The superplasticizer (SP) content of the mixtures was determined in next step. The last step dealt with the assessment of the global warming potential of the formulated Eco-SCC mixtures. The optimized Eco-SCC mixtures met all the requirements of self-consolidation in the fresh state. The 28-day compressive strength of such mixtures complied with the target range of 25 to 35 MPa. In addition, the mixtures showed sufficient performance in terms of drying shrinkage, electrical resistivity, and frost durability for the intended applications. The eco-performance of the developed mixtures was satisfactory as well. It was demonstrated in the last phase that the robustness of Eco-SCC is generally good with regards to water content variations and coarse aggregate characteristics alterations. Special attention must be paid to the dosage of SP during batching. / Résumé : Même si le béton est un matériau relativement vert, le volume astronomique de béton produit à travers le monde chaque année met le secteur de la construction en béton parmi les contributeurs important au réchauffement climatique. Le constituant le plus polluant du béton est le ciment en raison de son processus de production qui dégage, en moyenne, 0,83 kg de CO[indice inférieur 2] par kg de ciment. Le béton autoplaçant (BAP), un type de béton qui peut remplir le coffrage sans vibration externe, est une technologie qui peut offrir une solution aux problèmes de développement durable de l'industrie du béton. Cependant, toutes les exigences de la maniabilité du BAP proviennent d'une teneur en poudre plus élevé (par rapport au béton conventionnel), ce qui peut augmenter le coût de la construction et de l'impact environnemental du BAP pour certaines applications. Le BAP écologique, Éco-BAP, est un développement récent combinant les avantages du BAP tout en ayant une teneur en poudre significativement plus faible. La teneur en poudre maximale de ce béton, destinée à la construction du bâtiment et aux applications commerciales, est limitée à 315 kg/m[indice supérieur 3]. Néanmoins, la conception de l’Éco-BAP peut être difficile, car un équilibre délicat entre les différents ingrédients de ce béton est nécessaire pour garantir un mélange satisfaisant. Dans ce programme de doctorat, l'objectif principal est de développer une méthode systématique pour la formulation de l’Éco-BAP. Puisque l'effet de groupe des particules (EGP) est un paramètre clé pour la conception des mélanges l’Éco-BAP stables, et que ce phénomène est peu connu, dans la première phase de cette recherche, l’EGP est étudié. Cette partie se concentre sur l'influence de la granulométrie sur l’EGP et la stabilité des mélanges de modèle ainsi que des BAPs. Dans la deuxième phase, le protocole de formulation est développé, et les propriétés des mélanges obtenus, à l’état frais ainsi que l’état durcis, sont évaluées. Étant donné que l'évaluation de la robustesse est cruciale pour la production du béton à grande échelle, dans la dernière phase de ce travail, la robustesse d'un des mélanges les plus performants de la Phase II est examinée. Basé sur les résultats obtenus, nous constatons que l'augmentation de la fraction volumique d'une classe mène à une meilleure stabilité de cette classe. Cela contribue également à une EGP supérieure du squelette granulaire et à une stabilité plus élevée du système. Il a été montré qu'une granulométrie continue dans lequel la fraction volumique de chaque classe est plus grande que la classe consécutive plus grossière peut augmenter l’EGP. En utilisant une telle granulométrie, la fluidité d’un mélange du BAP pourrait être augmentée sans compromettre la résistance à la ségrégation. Un indice de prédiction du potentiel de la ségrégation de particules suspendues dans un fluide à seuil a été proposé. Dans la deuxième phase de la thèse, une méthode de conception en cinq étapes pour l’Éco-BAP a été développée. Le protocole de formulation commence par la détermination des teneurs en poudre et de l'eau, suivie par l'optimisation des fractions volumiques du sable et des gros granulats selon un modèle idéal de granulométrie (Funk et Dinger). La composition de poudre est optimisée dans la troisième étape afin de minimiser la demande en eau tout en garantissant une performance adéquate à l'état durci. Le dosage du superplastifiant (SP) est déterminé dans l’étape suivante. La dernière étape s’agit d’évaluer le potentiel du réchauffement climatique des mélanges développés. Les mélanges de l’Éco-BAP optimisés répondent à toutes les exigences à l'état frais pour le BAP. La résistance à la compression à 28 jours de ces mélanges est dans la fourchette cible de 25 à 35 MPa. En outre, les mélanges montrent des performances suffisantes en termes de retrait de séchage, la résistivité électrique, et la résistance contre gel-dégel pour les applications visées. La performance écologique des Éco-BAPs produis a été satisfaisante. Il a été démontré dans la dernière phase que la robustesse de l'Éco-BAP est généralement bonne en ce qui concerne les variations de teneur en eau et les changements de propriétés des gros granulats. Une attention particulière doit être accordée au dosage du SP pendant le malaxage.

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2017-02-02T00:09:36Z No. of bitstreams: 1 CONCRETO COM AGREGADO GRAU?DO RECICLADO DE CONCRETO_DOSAGEM E PRODUC?A?O.pdf: 3147518 bytes, checksum: 5fc02389f0e0978e3636005417e03f9e (MD5) / Made available in DSpace on 2017-02-02T00:09:36Z (GMT). No. of bitstreams: 1 CONCRETO COM AGREGADO GRAU?DO RECICLADO DE CONCRETO_DOSAGEM E PRODUC?A?O.pdf: 3147518 bytes, checksum: 5fc02389f0e0978e3636005417e03f9e (MD5) Previous issue date: 2016-08-04 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / A proper mix design and production must be done in order to increase the use of recycled concrete. The type of recycled aggregate (RA) used, the best replacement content, the best sequence and mixing time and the best way to evaluate the workability are some of the features that must be considered. Thus, this work was done to evaluate the mix design and production of concrete with concrete recycled coarse aggregate (RCA), using as a measure of workability the flow test in Graff?s table. Two levels of recycled coarse aggregate (20 and 40%), two levels of flow, for plastic and fluid mixtures, (350 and 400mm), and two mix design methods (IPT/EPUSP and ABCP) were evaluated on the concrete compressive strength, at 7 and 28 days of age. The results pointed out that the IPT/EPUSP mix design method was more suitable for recycled concrete. The flow test in Graff?s table, as a measure of workability, and the two stage mixture approach presented to be more suitable for the mix design and production of recycled concrete. Also, in this study, the concrete RCA content evaluated did not influence the compressive strength of concrete produced. So, it is completely feasible to use up to 40% replacement of NCA by concrete RCA. / Para ampliar o uso de concretos reciclados deve-se estabelecer a sua dosagem e produ??o considerando aspectos relacionados com o tipo de agregado reciclado (AR) utilizado, o melhor teor de AR, a melhor sequ?ncia e tempo de mistura e a melhor forma de avaliar a trabalhabilidade desses concretos. Assim, este trabalho foi desenvolvido com o objetivo de avaliar a dosagem e produ??o de concretos com ARs de concreto, usando como medida de trabalhabilidade o ensaio de espalhamento na mesa de Graff. Os teores de aplica??o do agregado gra?do reciclado(AGR) foram 20 e 40%. Foram avaliados dois n?veis de espalhamento (350 e 400mm) e dois m?todos de dosagem (IPT/EPUSP e ABCP). Os concretos foram avaliados ainda quanto a resist?ncia ? compress?o axial, aos 7 e 28 dias, e os resultados obtidos foram tratados estatisticamente atrav?s da an?lise de vari?ncia(ANOVA). Os resultados mostraram que o m?todo de dosagem do IPT/EPUSP apresentou-se mais adequado para a dosagem de concretos reciclados. O ensaio de espalhamento na mesa de Graff, como medida da trabalhabilidade, e o m?todo de mistura em duas etapas apresentaram-se adequados para a dosagem e produ??o de concretos reciclados. Nesse estudo, o teor de AGR avaliado n?o influenciou a resist?ncia ? compress?o dos concretos produzidos, sendo plenamente vi?vel o uso de at? 40% do agregado gra?do reciclado de concreto.

Este trabalho teve como objetivo analisar o comportamento do concreto leve com pérolas de poliestireno expandido (expanded polystyrene – EPS), para posterior utilização em estruturas pré-moldadas constituídas, por exemplo, por painéis de paredes e lajes sujeitas a ações mecânicas. Também foram considerados parâmetros de durabilidade e mecanismos de redução da porosidade. Dentre um universo de solicitações a que as estruturas de concreto leve podem estar submetidas, analisaram-se, para diferentes dosagens: resistência à compressão axial, módulo de elasticidade, absorção de água, resistência à tração na compressão diametral e na flexão. Foram incorporadas pérolas de EPS como componente para proporcionar redução do peso do concreto. Esse concreto leve pode, também, conter sílica ativa para reduzir a porosidade e melhorar a durabilidade das estruturas confeccionadas com esse material. As dosagens de concreto leve com EPS estudadas foram compostas basicamente por: cimento CPV-ARI, agregado miúdo (areia), pérolas de EPS, água e aditivo superplastificante. Ao final da pesquisa, após análise de 45 misturas, observaram-se ganhos de desempenho mecânico com a adição de sílica ativa, adição de fibras de aço, ajuste na granulometria do agregado miúdo e redução do teor de EPS nas misturas, obtendo-se resistência à compressão na ordem de 16 MPa e massa aparente de 1370 kg/m³, com fator de equivalência (FE) correspondente ou superior ao de um concreto convencional de 20 MPa e 2400 kg/m³. Deve-se ressaltar que o emprego de EPS no concreto reduz o peso dos elementos de construção, estruturais ou não, e o consumo de agregados (areia e brita ou seixo), do mesmo modo que o uso de adições minerais reduz o consumo de cimento. / This study aimed to analyse the lightweight concrete behavior with expanded polystyrene beads (EPS beads) for later use in precast structures made of walls panels and slabs, for example, structures under mechanical actions. Durability parameters and mechanisms of porosity reduction were also considered. Among a universe of requests which structures of lightweight concrete can be submitted, were analysed to different mix designs: compressive strength, modulus of elasticity, water absorption, tensile strength in the splitting and in the flexure tests. EPS beads were incorporate as raw material to provide weight reduction to the concrete. This lightweight concrete can also have silica fume to reduce its porosity and to improve durability of structures made with this material. The lightweight concrete mix designs studied were basically composed by: high initial strength cement, small aggregate (sand), EPS beads, water and superplasticizer additive. At the end of the research, after 45 mixtures analysis, mechanical performance gains were observed with the addition of silica fume, addition of steel fibers, adjusting in the fine aggregate\'s particle size and reducing of EPS content in the mixtures, obtaining compressive strength in the order of 16 MPa and apparent mass of 1370 kg/m³, with equivalence factor (EF) corresponding to or higher than that of an ordinary concrete of 20 MPa and 2400 kg/m³. It should be emphasized that the use of EPS in the concrete reduces the weight of the building members, whether structural or not, and the aggregates consumption (sand and gravel or pebble), in the same way as the employment of mineral additions reduces the consumption of cement.